tsl2550 ETC-unknow, tsl2550 Datasheet - Page 8

• Manufacturer Part Number: tsl2550
• Description: Ambient Light Sensor With Smbus Interface
• Manufacturer: ETC-unknow

TAOS029 – SEPTEMBER 2002
Command Register
8
Copyright E 2002, TAOS Inc.
The command register contains eight bits as described in Table 1 and defaults to 0 (0x00) at power-up. A
command summary appears in Table 2.
The command register is used primarily to select which register will be read during a read cycle (RSEL) and
to control the power consumption of the device (ADCEN and PON). When ADCEN and PON are high, the device
is in the full powered-up state and is fully operational. When ADCEN and PON are low, both the ADC and the
internal oscillator are powered down, resulting in minimum power consumption. Both ADCEN and PON should
always be asserted and de-asserted together . The remaining bits (B4, B3, and B2) in the command register
should always be written 0. For details on using the command register, see the Operation section, below.
RESERVED
RSEL2
ADCEN
FIELD
RSEL
PON
B7
COMMAND
00h
03h
43h
83h
RSEL1
RSEL
7 to 5
4 to 2
BITS
B6
1
0
Table 1. Command Register Data Format
Read Data Select. This field determines the data output by the TSL2550
during read.
Field Value
000
010
100
Reserved for factory test. These bits should always be written to 0.
ADC Enable. This field actives the ADC. Writing a 1 activates the ADC.
Writing a 0 disables the ADC. ADCEN is normally used in conjunction with
PON.
Note: Both ADCEN and PON must be asserted before the ADC channels will
operate correctly.
Power ON. This field activates the internal oscillator to permit the timers and
ADC channels to operate. Writing a 1 activates the oscillator. Writing a 0
disables the oscillator. PON is normally used in conjunction with ADCEN.
Note: For the Duration of writes and reads over the SMB interface, this bit is
overridden and the oscillator is enabled, independent of the state of PON.
Note: Both ADCEN and PON must be asserted before the ADC channels will
operate correctly.
Place device in power-down state
Read command register
Read ADC Channel 0
Read ADC Channel 1
RSEL0
B5
t
Table 2. Command Summary
www.taosinc.com
B4
0
RESERVED
Read Value
Command register
ADC channel 0
ADC channel 1
B3
DESCRIPTION
0
FUNCTION
B2
0
t
ADCEN
ADCEN
B1
The LUMENOLOGY r Company
PON
PON
B0